Interpersonal Psychotherapy (IPT) is a well-described and empirically validated treatment for depression. Though its efficacy is unassailable, it is ofte delivered with low fidelity in the community, decreasing its effectiveness. This in turn diminishes the response and recovery rates of patients treated in the community. This proposal is submitted in response to NIMH RFA-MH-12-505, Optimizing Fidelity of Empirically- Supported Behavioral Treatments (ESBT) for Mental Disorders. This RFA specifically requests that proposals develop and test: 1) methods for assessing theory-derived ESBT fidelity components; and 2) interventions that enhance and maintain the fidelity with which clinicians implement ESBT's in community settings. In response, we propose to conduct a two-phase study involving IPT. Phase I will be a two year project to develop and validate a fidelity instrument to measure the adherence and quality of the delivery of IPT. Specific steps include a review of all available psychotherapy adherence instruments and review of IPT videotapes with qualitative feedback by IPT and other psychotherapy experts, with subsequent development of a prototype measure of IPT fidelity. This measure will then be pilot tested using archived samples of IPT from outcome studies, allowing us to correlate adherence to specific IPT tactics and techniques to symptomatic and diagnostic outcome. We will develop a final IPT adherence measure which will be used by IPT experts to rate a representative sample of IPT therapy sessions. We will also use the instrument to rate cognitive and psychodynamic therapy sessions as a means of establishing discriminant validity. Phase II will be a three year project in which the fidelity measure will be used to evaluate 4 different methods of IPT training in the community, with the goal of establishing the feasibility of training methods that foster fidelity to IPT and optimize patient outcomes. These methods include a traditional instructor- led didactic training followed by either: 1) individual case supervision; 2) community-based consultation; 3) internet-based training; or 4) an autodidactic control condition. The IPT training will occur in community mental health agencies serving a diverse and low-income population in Los Angeles and other California communities, all of which have a close liaison relationship with the PI. In sum, our goals are to develop and test a measure of the fidelity of IPT treatment delivery which: 1) has content validity; 2) has a high degree of predictive and discriminative validity; 3) is reliable; 4 is comprehensive; 5) reflects the stages of IPT; and 6) is feasible for use in the community.